All Questions
Tagged with cosmology dark-matter
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Gondolo-Gelmini Change of Variables
In the article Cosmic abundances of stable particles: Improved analysis, P. Gondolo and G. Gelmini, Nucl. Phys. B 360 (1991), p. 145-179, they convert $\rm{d}^3p_1\rm{d}^3p_2=2\pi^2p_1p_2\rm{d}E_1\rm{...
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Dark matter in the time window between freeze-out and kinetic decoupling
Background
After the freeze-out, when all annihilations have stopped, the abundance ($Y=\frac{n}{s}$) of thermal dark matter species no longer changes with time. However, it is still kept in kinetic ...
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Gravitational halos made of neutrinos...?
I have been recently interested in how halos made of standard model particles could be formed and behave.
After asking some questions in this site, I was told about how neutrinos could form such halos....
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Are modified theories of gravity credible?
I'm a statistician with a little training in physics and would just like to know the general consensus on a few things.
I'm reading a book by John Moffat which basically tries to state how GR makes ...
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If dark matter is axion particles, how did such light particles slow down?
One candidate for dark matter is axions and there is tentative experimental evidence for their existence.
Axions are very light, most models weigh them in at tiny fractions of an eV. It seems like ...
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Does neglecting dark matter solve the Hubble tension?
If the total mass of the universe is smaller than estimated by neglecting the gravitational pull of dark matter, the estimated expansion rate should be greater.
Does this consideration in the CMB ...
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What's the meaning of 'cold' in the CDM model?
On Wikipedia, it says
In cosmology and physics, cold dark matter (CDM) is a hypothetical type of dark matter. According to the current standard model of cosmology, Lambda-CDM model, approximately 27% ...
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Test of the primordial black hole solution to dark matter
One of the ideas that might solve some of the dark matter problem are the existence of many small black holes. There is evidence, in principle, for the existence of these small black holes via the ...
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How are the dark matter (DM) thermalization rates derived in singlet DM model?
This well-cited paper talks about a minimal renormalizable extension to the Standard Model (SM) to incorporate particle dark matter (DM) into it by adding a real scalar field $S$ which (unlike the ...
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Why do people say that the $\Lambda$-CDM model has six independent parameters?
The Wikipedia article on the $\Lambda$-CDM model says that the model has six "independent parameters". It also says that the model has several "fixed" parameters and several "...
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Is it possible that dark matter and dark energy come from the same dark particle?
I've skimmed articles/blogs and watched videos around this issue, and the universal consensus is that dark matter and dark energy are two different things >> DM is attractive while DE is ...
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What if gravitation was the only force? [closed]
This is a follow up of Interactions within constituents of dark matter .
I wonder about dark matter, and, naturally, compare it with our observable world.
If gravitation would be the only force acting ...
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Is Dark Energy Taking Over?
First question, trying to keep it simple 😃
Because it's constant it grows in magnitude as the universe expands, whereas normal matter does not? Is this accurate as far as we know?
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Is the amount of dark matter per galaxy the same as you look back through time (further away from earth)?
In the hope that it may inform us about the development/evolution (if any) of dark matter over time, are there any differences (eg. in structure or concentration) in the dark matter at large radial ...
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"Penrose Functional Degrees of Freedom" ( PFDoF) as a source of dark mass
In his book "Fashion, Faith, and Fantasy in the New Physics of the Universe" Sir Roger Penrose mention ( referring to his older works and specially Penrose-Hawking Theorem) the possibility ...
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